Apples, celery and strawberries led this years' Environmental Working Group's (EWG) list of Dirty Dozen fruits and vegetables and virtually every media report of the list led off with a picture and chilling headline about apples being the moist pesticide-laden fruit. Joe Schwarcz reports, "EWG claims that it is not out to scare the public, that it only strives to alert consumers as to which fruits and vegetables harbor the most pesticides and should therefore by purchased in their organic version is possible," (1) A better description of the list is fearmongering.
Clearly, most of the media made no attempt to really analyze the data since they prefer the scare tactic. So that leaves the public with a major unanswered question. How much pesticide and is it really harmful? Joe Schwarcz analyzed the data dredging and found that, for apples, the average amount of pesticide detected was 2.5 percent of the EPA tolerance dose. (1)
A person would need to eat so much of the produce on the Dirty Dozen you can't even imagine said Dr. Marion Nestle, author and professor of nutrition, food studies and public health at New York University. (2)
Here are some addition data. The USDA tested 744 apple samples from across the country and for 194 pesticides. A total of 140,881 tests were performed, with residues being detected in 3,717 cases. Only 2.6 percent of tests detected any pesticide residue!
What about other studies on pesticides? Research published earlier this year in the peer-reviewed
Journal of Toxicology using the same USDA data from 2004 to 2008, said scientists found the levels of pesticides in 90 percent of cases from the 2010 Dirty Dozen list were at least 1,000 times lower than the chronic reference dose--the concentration of a chemical a person could be exposed to on a daily basis throughout life before risking harm. (2)
All this reminds one of the Alar scare of the past. After all the posturing and bad news about Alar, which cost the apple industry more than $100 million and a number of small-scale growers put out of business, it was determined by the National Cancer Institute and the EPA that Alar failed to cause cancer except in doses between 100,000 and 200,000 times the normal amount a child might consume in a day's ration of apple products. (3)
"Pesticides have one indisputable effect: they cause emotions to boil over. That's just what happened when a group of golfers noticed that a chemical sprayer out on the course as they were completing their round. By the time they got into the clubhouse, several were complaining of headaches, rashes and general malaise, and angrily approached the superintendent to protest what they believed was an irresponsible activity. The golfers linked their symptoms with the chemical being sprayed on the grounds because they were convinced that the use of pesticides is inherently unsafe," reports Joe Schwarcz. It turns out that the dastardly chemical being spayed on the golf course, the one that caused such severe reactions in the golfers was good old water. As Schwarcz observes, "Fear itself can sometimes be hazardous." (4)
If you worry about this type of thing, here is something that will really set you off. We get much more natural pesticides than synthetic pesticides in our diet. Bruce Ames and his colleagues at the University of California, Berkeley, report that about 99.99 percent of all pesticides in the human diet are natural pesticides from plants. All plants produce toxins to protect themselves against fungi, insects and animal predators, such as man. Tens of thousands of these natural pesticides have been discovered, and every species of plant contains its own set of different toxins, usually a few dozen. When plants are stressed or damaged (such as during a pest attack), they increase their levels of natural pesticides manifold, occasionally to levels that are acutely toxic to humans. Ames estimates that Americans eat about 1,500 mg per person per day of natural pesticides and that a person annually ingests about 5,000 to 10,000 different natural pesticides and their breakdown products. (5)
Now some words about celery, strawberries, numbers 2 and 3 on the Dirty Dozen list. Celery is a case that sheds light on the sometimes double-edged nature of organic agriculture. Celery defends itself by producing psoralen, a toxin that can damage DNA and tissue and also causes extreme sensitivity to sunlight in humans. Sharon Moalem reports, "The thing about celery is that it's especially good at kicking psoralen production into high gear when it feels under attack. Bruised stalks of celery have 100 times the amount of psoralen of untouched stalks. Farmers who use synthetic pesticides, while creating a whole host of other problems, are essentially protecting plants from attack. Organic farmers don't use synthetic pesticides, so that means celery farmers are leaving their growing stalks vulnerable to attack by insects and fungi--and when those stalks are inevitably munched on, they respond by producing massive amounts of psoralen. By keeping poison off the plant, the organic celery farmer is all but guaranteeing a biological process that will end with lots of poison in the plant." (6)
There are more than 1,000 chemicals in strawberries (7), yet we happily eat strawberries even though one of these chemicals is acetone, a known neurotoxin. (8)
Lastly, some words about "organic." Just because it's organic doesn't mean food is pesticide-free. Alex Avery reports research revealed that one-fourth of all fruits and vegetables marketed as organic had significant residues of synthetic pesticides in them. Further, nearly a third of the time when the synthetic residues were found on organic produce, they were present at a concentration even higher than the average levels found on conventional fruits and vegetables. However, if you are an organic food proponent, before throwing your food into the garbage can, realize that this research has very little to do with real food safety. Just like the Dirty Dozen report, the traces of synthetic pesticides on both the conventional foods and the organic foods were well below safety levels set by the government. (9)
Our bodies handle all chemicals in the same way, regardless of their origin. However, the popular notion remains that the greatest health threat is posed by synthetic chemicals in our food. And this fallacy is often encouraged by newspaper headlines and television reports warning of the danger posed by some additive or pesticide in our food. Remember this the next time you hear the food scare of the month and put it in perspective with the myriad of natural chemicals in the foods we eat.
References
1. Joe Schwarcz, "Apple-picking of data leaves bad taste,"
Montreal Gazette, June 25, 2011
2. Kelly April, "Dirty Dozen Debate,"
Los Angeles Times, June 22, 2011
3. James P Collman,
Naturally Dangerous, (Sausalito, CA, University Science Books, 2001), 3
4. Joe Schwarcz,
The Fly in the Ointment, (Toronto, Canada, ECW Press, 2004), 39
5. B. N. Ames and L. S. Gold, "Paracelsus to parascience: the environmental cancer distraction,"
Mutation Research, 447, 3, 2000
6. Sharon Moalem,
Survival of the Sickest, (New York, William Morrow, 2007), 86
7. Sherman K. Stein,
Strength in Numbers: Discovering the Joy and Power of Mathematics in Everyday Life, (New York John Wiley & Sons, 1996), 21
8. Joe Schwarcz,
Let Them Eat Cake, (Toronto, Canada, ECW Press, 2005), 159
9. Alex Avery, "Natural Mistake," Hudson Institute, May 29, 2002
